Reconstruction of Dose

Bethlehem Steel Corpo

James W. Neton, Ph.D., 

NIOSH / OCAS

May 4, 2004
Discussion Topic

• Types of Radiation Exposure• Properties of Uranium• The Bethlehem Steel Site Prof

(Technical Basis Document)

• An Example Calculation• The Residual Contamination R
Types of Radiation Ex

• Internal Exposure

− From uranium deposited in the − Pathways are inhalation, ingest

absorption

• External Exposure

− From exposure to uranium met

the body such as uranium billet

− Skin dose much greater than or
Properties of Urani

• Emits alpha, beta, and gamm• With the exception of skin, ex

dose to body is fairly low

• Concentrates in only a few int

organs 

• When inhaled, dose to lung ca

large

• Absorption from GI tract is low 

insoluble forms)
Distribution of Uranium 

Body

Skeletal System 

Kidneys
Site Profiles / Technica

Documents

• Serve as guides for Health Ph

doing dose reconstructions

• Ensure a standard, consistent 

for each case

• Data collected from a number 

sources

• Reviewed and approved by N• Living Documents
Bethlehem Steel Technica

Document (TBD)

• Covered employment period is 1

1952

• NIOSH research found evidence 

individual rollings during 1951 an

• TBD assumes 48 rollings (one pe

between 1949 and 1952

• Estimates inhalation intake using 

concentration data

• Assigns a distribution of values u

times the maximum allowable co
Bethlehem Steel Technica

Document (continued

• Assumes a 10 hour work day with 

breathing

• Uses claimant favorable solubility 

types of uranium

• External exposure estimate based 

radiation properties of uranium

• Ingestion pathway not explicitly ad

– NIOSH is currently revising the TBD 

pathway

– Not expected to substantially increas
Calculation of Internal Dos

Upper Limit Air Concentr

• Assumptions

– Worker was employed during th

four year covered period

– Regardless of job classification 

present during all 48 modeled r

– Worked 10 hour days at a heav

rate

– Inhaled worse case solubility ty

uranium
Total Internal Dose to Se

Organs 30 Years after Inh

OrganLungsBoneKidneyLiverColonPancreasStomachBladder

Effective Dose 

3165

216

9031

7666
Probability of Causati

• Determination of the chance that a 

the result of exposure to uranium Bethlehem Steel

• Calculated at the 99% credibility le• Based on NCI Interactive Radioep

Program (IREP)

• Incorporates the effect of many va

the outcome such as cancer type, diagnosis, and time since first exp
PC uncertainty for leuk

example: man exposed to 11 rem age 40, diag

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0 10 20 30 40 50 60 70 

Probability of Causation ( % )

Probability density Upper 99% PC = 

Median estimate of PC = 34%
0

1020304050607080

10

rem

20

rem

30

rem

40

rem

50

rem

60

rem

70

rem

r

Percent

50 year old at diagnosis 60+ year old a

Prostate Cancer

30 year latency

Inputs: >200 keV photons 30 yr latency, lognormal dist, SGD=2
Probability of Causati

(continued)

• Organs that concentrate uran

have a higher internal dose) hhigher PC values than those t

• Contribution of external dose 

internal organs is small

• Although skin doesn’t concen

uranium, external exposures chigh, thus resulting in high PC 
Residual Contamination Rep

• Draft report received from NIOSH’s c

May 19, 2003

• NIOSH received Congressional requ

dates of contamination periods on M

• NIOSH evaluated each facility and m

for 96 out of 219 facilities in the repo

• A cut and paste error inadvertently id

as having residual contamination oucovered period
Additional Informat

• Contact the NIOSH Office of 

Compensation Analysis and S(OCAS) at 800-356-4674 or 56800 

• Visit our website at:

www.cdc.gov/niosh/ocas

• E-mail us at ocas@cdc.gov